What else can I write about an advertisement? It persuades viewers to not smoke, and shows a bloody hand holding a cigarette.

Without knowing exactly what anti-smoking commercial/advertisement you are discussing, I will encourage you to analyze the persuasive techniques used and how effective they are.

There are common techniques used in advertising (both print, audio, and film/TV) which you should look for in the example you must analyze. Use the list below:

Bandwagon: "everyone" is using (or not using) the product

Celebrity endorsement: is someone famous featured? Consider in audio, is a famous voice used?

Emotional...

Without knowing exactly what anti-smoking commercial/advertisement you are discussing, I will encourage you to analyze the persuasive techniques used and how effective they are.

There are common techniques used in advertising (both print, audio, and film/TV) which you should look for in the example you must analyze. Use the list below:

Bandwagon: "everyone" is using (or not using) the product

Celebrity endorsement: is someone famous featured? Consider in audio, is a famous voice used?

Emotional appeal or transference: the ad is designed to trigger a specific emotion which the audience may then transfer to the product. (In this case, perhaps the emotional appeal is fear. The ad is somewhat scary making the audience believe cigarettes are somewhat scary.)

Humor

Plain/average people: appeals to the everyday/common person.

Individuality/anti-bandwagon: sends the message that not everyone is doing it, therefore by doing it you will be unique.